Monday, March 31, 2008

Middle-Aged Users' Declining Web Performance

Targeting aged users ...

"Between the ages of 25 and 60, people's ability to use websites declines by 0.8% per year — mostly because they spend more time per page, but also because of navigation difficulties.

Based on extensive research, we've developed special Web usability guidelines for young children, teenagers, and senior citizens. Each of these age groups have specific characteristics that designers must understand to attract young or old users to their sites.

But what about people in the middle? We don't even have a real name for them — I usually just call people between 25 and 60 years old "mainstream users." This is by far the most important age group for several reasons:

* There are more of them than in the young or old age groups. In the U.S., 49% of the population is between 25 and 60 years old (35% are younger and 16% are older).
* Mainstream users have all the good jobs; they're the richest, and they spend the most money online.
* Almost all B2B sites target this age group. This is especially true if we extend the "mainstream" definition to include people up to 65 years old; beyond that, we officially start calling them "seniors" in our usability research.
* Virtually all intranet users fall within this group, especially if we extend the age range to 65.

I just finished analyzing the quantitative data from our study last month to update the course on Fundamental Guidelines for Web Usability. We have stunning new statistics for important Web behaviors like search and scrolling, as well as notable numbers to quantify user attention. All of these will be presented at my upcoming usability conference.

We also got insights into middle-aged users that I couldn't fit into my presentation. In programming the conference, I focus relentlessly on giving attendees "news you can use," so we cover only the most important findings for maximizing a website's business value. As you'll see, the following age-dependent data doesn't meet this criterion. It's interesting, but doesn't have a high-ROI factor. Luckily, cyberspace has fewer constraints than real-time events, so I can write a column about the purely fascinating (but not money-making) slides I had to cut. Here we go:
User Performance Data by Age
Between the ages of 25 and 60, the time users need to complete website tasks increases by 0.8% per year.

In other words, a 40-year-old user will take 8% longer than a 30-year-old user to accomplish the same task. And a 50-year-old user will require an additional 8% more time. (Mathematically inclined readers will note that this increase is linear, not exponential.)

This finding is statistically significant at the 5% level, given the 61 users in our study.

Does this mean that people in their 40s or 50s can't do their jobs? Not at all. There are many other ways in which people get better with age.

Individual differences swamp the tiny age-related difference in the 25- to 60-year-old group. Users are extraordinarily variable in their use of websites and intranets.

I have a 5-5-5 rule for task times while using websites: Across a broad range of studies, our data shows that

* the slowest 5% of users are
* about 5 times as slow
* as the fastest 5% of users,

meaning that the slowest users need 400% more time to perform the same tasks. The 0.8% difference caused by each year of aging pales in comparison.

So, a fast 50-year-old will beat a slow 30-year-old every day — by several hundred percent."    (Continued via Jakob Nielsen's Alertbox)    [Usability Resources]


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